ST. LOUIS PARK, Minn. -- While the City of St. Paul warns fossil hunters at Lilydale Regional Park about potentially hazardous and unsafe conditions in the park, some of the parents whose children were injured and killed in a May 2013 landslide there during a school field trip say the school didn't tell them about the dangers.

Four days after his 9-year-old son Haysem Sani was killed by a landslide, Mohamed Muse visited Lilydale Regional Park with his cell phone camera in hand.

"Look at here where my son is dying," says Muse on the video when he finds the place where his 9-year-old son Haysem Sani lost his life. "This is a dangerous place. How you gonna bring kids here."

Today, the trail in Lilydale Park remains closed.

"We trusted the school you know like our family," says Muse.

Haysem's parents, along with the parents of 10-year-old Mohamed Fofana, who was also killed, and 10-year-old Devin Meldahl who was buried alive but survived, all say they wish they had known more about Lilydale, about the bluffs and the steep, winding and rocky terrain.

"That's a very, very dangerous place. Why they allowed to go over there?" Muse asks.

You need a permit from the St. Paul Parks and Recreation Department to fossil hunt at Lilydale. And the applicant has to sign a waiver, essentially agreeing that the City isn't responsible for anything that might happen.

The waiver specifically states that some of the "conditions and locations" in Lilydale are "hazardous", even "unsafe".

In April, a fourth grade teacher applied for the permit on behalf of Peter Hobart School and electronically signed the waiver, "certifying" and accepting "responsibility" for making the conditions of the permit and the waiver "known to all participants...or in the case of minors, to their parents/guardians."

But the parents whose children were killed and injured say no one told them about the waiver or the hazards at the park.

In fact, parents say they only signed a blanket field trip permission slip at the start of the school year. The slip applies to all field trips and does not mention anything at all about Lilydale, stating only that "teachers" will provide parents with "other relevant information" about each trip.

And the school did that in an information flyer given to students before the field trip.

"He say he want to go," says Sartu Nagayo about her son Haysem's excitement about the field trip.

Haysem told his mother about the field trip the night before, but she didn't see the flyer until two weeks after his death when she found it in his backpack.

"He said we're going to go look for fossils. That's the only thing I know," says Sartu.

The flyer states that the students will be taking a "fossil finding class" at Lilydale, mentions lunch and the need for sturdy shoes, but nothing at all about unsafe conditions at Lilydale. And at the bottom, the flyer references the permission slip parents signed at the beginning of the year.

"I was going to play football this year," says Devin Meldahl who was buried by the landslide and severely injured. "I like to play football. I like to go outdoors and hunt and fish. I like to play basketball, baseball. I like to ride my bike."

Devin faces a long recovery. His mother Danielle says she did see the Lilydale flyer before the field trip, but didn't think anything of it.

"It didn't say anything that stuck out to me that it was going to be not a safe place to go," says Danielle.

Even the districtwide field trip policy in St. Louis Park states that field trips will be conducted in a "safe environment."

"You don't think that the school might bring them in a place that's not exactly safe or they'll notify you first," says Danielle.

Many schools go fossil hunting at Lilydale Park.

And we've learned that the parents of students at Buffalo Community Middle School were notified about potential hazards before their kids went that very same day. The permit waiver language was laid out in Buffalo's permission slip. Danielle Meldahl wishes she had the same warning.

"Because I don't think I would have let Devin go," she says.

But whether teachers or administrators at Peter Hobart had to or should have told parents more is up for debate.

Lilydale is not unlike many wild, nature areas in Minnesota. City officials describe it as largely natural, unmanaged.

The field trip flyer does state that kids should be prepared for hiking, climbing and getting muddy.

And St. Paul issues about 400 fossil hunting permits every year. Even Peter Hobart had been there before without incident.

"It's a great experience for those kids," says parent Kasey Shipp.

Shipp's daughter Kylie was on this year's fossil hunting trip when the landslide happened. Her two older kids have been on the field trip as well. She says the school gives plenty of information ahead of time.

"There's no way that you would have been able to know that that was going to happen," says Kasey. "It's just a crazy accident."

It's something that could ultimately play a role in any potential legal fight. Minneapolis attorney Bob King is a veteran trial lawyer who once won a settlement from Roseville Schools after a student drowned on a field trip. He says winning a case like that can be difficult.

"If there is a lawsuit, it's going to turn on what a reasonably prudent school district would've, should've done," says King.

The St. Louis Park school district turned down repeated requests from KARE 11 and Minnesota Public Radio News for an interview about what happened that day and what parents were told about the field trip, saying only in a written statement that it cannot provide any specific information about the incident, citing the privacy rights of the people involved.

The district did, however, answer some questions.

According to St. Louis Park Public Schools, there were 46 children on the field trip, supervised by two teachers, two para-professionals, seven adult chaperones and a paleontology guide.

An adult we spoke with who was there that day said the children were supervised at all times and not just allowed to go anywhere they wanted in the park, including the kids who were injured and killed.

The district also provided us with the field trip permission slip parents received at the start of the school year.

But we still have a lot of unanswered questions.

We don't know, for example, what other verbal or written instructions or safety information students, teachers or chaperones got ahead of time.

An attorney for the district denied our other data requests citing the potential for a civil lawsuit, although no lawsuit has been filed.

Some of the families, however, are considering their legal options.

The City of St. Paul hired an engineering firm to study the area after the landslide and then hired an attorney to conduct an independent investigation.

The city has not shared any of the results with us and has not answered some of our requests for public data, funneling all of the requests through the mayor's office.

A fourth child, Lucas Lee, was also injured in the landslide. He had a broken ankle. His parents say he is recovering physically, but is still struggling emotionally with what happened.